13.3 Amiodarone, Lidocaine & Adenosine

Antiarrhythmics in Context: Arrest vs Pulse-Present

PALS learners often memorize drug names without mapping them to the correct algorithm box. Amiodarone, lidocaine, and adenosine appear in multiple chapters; this section is the dose-and-technique table that ties them together.

High-level map

Shock-refractory VF / pulseless VT

When VF or pVT persists despite high-quality CPR and defibrillation, an antiarrhythmic may be given during CPR:

• Amiodarone 5 mg/kg IV/IO bolus, maximum 300 mg; the 2025 Pediatric Cardiac Arrest Algorithm permits repeating up to 3 doses, with subsequent doses capped at 150 mg each, or
• Lidocaine 1 mg/kg IV/IO loading dose as the accepted alternative—current teaching is that either may be considered; do not treat the exam as "amiodarone only forever" or "lidocaine is obsolete."

The amiodarone caps in practice

Weight-based math and the 300 mg first-dose ceiling cross at 60 kg. Below that weight the cap never binds; above it, the cap does the work:

Priorities that still outrank debating amiodarone vs lidocaine:

1. Continuous high-quality CPR
2. Correct energy shocks (2 J/kg, then 4 J/kg, up to max per algorithm)
3. Epinephrine on interval
4. Reversible causes

Antiarrhythmics are adjuncts for refractory shockable arrest—not substitutes for defibrillation.

Worked amiodarone arrest examples

Give IV/IO during CPR; flush; minimize interruptions. Watch for post-ROSC hypotension and bradycardia—amiodarone is not hemodynamically free.

Adenosine for SVT: Dose, Maxima, and Rapid-Push Technique

Adenosine briefly blocks the AV node. It can terminate reentrant SVT that uses the AV node and can reveal underlying atrial activity. It is not the drug for sinus tachycardia, not first-line for unstable SVT (use synchronized cardioversion—Chapter 10), and not appropriate as casual therapy for irregular wide-complex rhythms concerning for pre-excited AF.

Dosing table (PALS teaching)

Worked examples

• 8 kg infant: first 0.8 mg, second 1.6 mg (well under adult-style maxima).
• 40 kg child: first 4 mg, second 8 mg.
• 70 kg adolescent near adult size: first dose may hit the 6 mg teaching cap; second may hit 12 mg—know that weight-based dose and maximum both constrain the syringe.

Rapid push technique (as important as the milligrams)

Adenosine’s half-life is only seconds. Technique failures look like "drug didn’t work" when the drug never reached the heart:

1. Use the most proximal IV practical (or IO with vigorous flush).
2. Draw drug in one syringe; saline flush in another (or use a stopcock system).
3. Push adenosine as fast as possible.
4. Immediately push a rapid saline flush to clear the line into central circulation.
5. Elevate the extremity if using a distal peripheral IV and that is your system’s method.
6. Record a continuous rhythm strip; warn the team to expect brief asystole, pauses, or ventricular escape beats.

If SVT persists after two appropriate doses, reassess stability. Unstable → synchronized cardioversion 0.5–1 J/kg then 2 J/kg. Expert consultation for refractory cases; 2025 materials may mention additional advanced options (e.g., IV sotalol in highly selected refractory pathways)—not first-line stable SVT care.

Adenosine is not a wide-complex panacea

Pulse vs Arrest Administration: Amiodarone’s Critical Difference

The milligram number 5 mg/kg appears for amiodarone in both arrest and some pulse-present VT pathways. The administration method changes with perfusion status—and exams love that distinction (Chapter 10 preview, reinforced here).

Arrest (no pulse, refractory VF/pVT)

• Give amiodarone as a resuscitation bolus IV/IO during CPR.
• Goal: deliver drug rapidly into low-flow circulation while shocks and compressions continue.
• Hemodynamic side effects are secondary to the fact that the child currently has no output.

Pulse present (perfusing VT / selected wide-complex pathways)

• Same 5 mg/kg IV/IO teaching dose order of magnitude.
• Give over a period of time (controlled infusion), not as a reckless slam that drops blood pressure.
• Monitor continuous ECG and blood pressure; have pads on; prepare for cardioversion if the child destabilizes.
• Expert consultation is preferred before stacking agents.
• Do not casually combine amiodarone with procainamide or other antiarrhythmics—additive proarrhythmia and hypotension risk.

Lidocaine notes

Lidocaine remains an accepted alternative antiarrhythmic for shock-refractory VF/pVT and appears in some pulse-present ventricular arrhythmia protocols. Know:

• It is a valid either/or partner to amiodarone in refractory arrest teaching—not a "wrong answer" by default.
• Local cards list exact mg/kg bolus and infusion limits—memorize amiodarone 5 mg/kg cold; know lidocaine is the named alternative without inventing non-card numbers if your materials vary.
• Toxicity includes neurologic symptoms (tinnitus, seizures) and myocardial depression at high levels—another reason dosing aids matter (Section 13.4).

Side-effect and safety cluster

Clinical scenarios

Refractory VF: 18 kg child, still VF after CPR and defibrillation attempts with epinephrine on board. During CPR give amiodarone 5 mg/kg = 90 mg IV/IO (or lidocaine alternative), flush, continue shocks/CPR.

Stable SVT: 12 kg infant, rate 280, good perfusion. After ice to face fails: adenosine 1.2 mg rapid push + flush; if needed 2.4 mg second dose; strip recording on.

Perfusing VT: 25 kg child, monomorphic VT, BP acceptable, mentating. Expert-guided amiodarone 5 mg/kg = 125 mg over time, pads in place—not a 125 mg slam identical to arrest technique while ignoring blood pressure.

Bottom line for 13.3: Refractory VF/pVT → amiodarone 5 mg/kg bolus or lidocaine; SVT → adenosine 0.1 then 0.2 mg/kg rapid push + flush (maxima often 6/12 mg); pulse-present amiodarone → 5 mg/kg over time; never let drug choice replace electricity when the algorithm demands a shock.